Field
The present disclosure relates generally to communication systems, and more particularly, to downlink control information message design for multi-user superposition transmission (MUST).
Background
Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.
These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT)), and other requirements. Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. There exists a need for further improvements in 5G NR technology. These improvements may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.
Wireless networks support MU-MIMO transmission in which a base station transmits multiple spatial layers or spatial streams over a shared downlink resource to multiple user equipments (UEs). For example, the base station may provide a first downlink control information (DCI) message to a first UE allocating a downlink resource to the first UE for receiving transmissions from the base station. The base station may also provide a second DCI message to a second UE allocating the same downlink resource for receiving transmissions from the base station by the second UE. However, the first DCI message may not indicate that the downlink resource is also allocated for transmissions directed to the second UE. As such, when the first UE receives a transmission from the base station, the first UE may not be aware of interfering signals or may have to do a series of blind detections for potentially interfering signals, and the blind detections may consume resources and battery power.
Although wireless networks support multi-user multiple-input-multiple-output (MU-MIMO) transmission, a user equipment receiving a downlink resource grant may not be aware of other user equipments that may also have received the same downlink resource grant. As such, the user equipment may not be able to accurately and efficiently decode the subsequent downlink transmission.